1. Technical Field
The present disclosure relates to a distinguishing circuit for a BIOS (Basic Input Output System) chip.
2. Description of Related Art
When designers design a computer system, a plurality of computer systems with different peripheral devices are designed simultaneously. For example, a first type of computer system will include an optical disk drive, and a second type of computer system will include a floppy disk drive. The other components of the first and second types of computer systems may be the same. As a result, programs loaded in BIOS chips in the first and second types of computer systems will be different.
In current computer system, the BIOS chip reads signals Chassis_ID1 and Chassis_ID2 to distinguish the first and second types of computer systems. Referring to FIG. 2, a distinguishing circuit includes four resistors R1, R2, R3, and R4. A 3 volt power supply +3V is grounded through the resistors R1 and R2 connected in series. The 3 volt power supply +3V is further grounded through the resistors R3 and R4 connected in series. A node between the resistors R1 and R2 is connected to a BIOS chip 100 for outputting the signal Chassis_ID1. A node between the resistors R3 and R4 is also connected to the BIOS chip 100 for outputting the signal Chassis_ID2.
When the computer system is the Chassis ID1 type, the resistors R2 and R3 are taken off. At this time, the signal Chassis_ID1 is received by the BIOS chip 100 at a high level, and the signal Chassis_ID2 is received by the BIOS chip 100 at a low level. The BIOS chip 100 determines that the computer system is the first type (Chassis ID1), and loads corresponding programs. When the computer system is the second type (Chassis ID2), the resistors R1 and R4 are taken off. At this time, the signal Chassis_ID1 received by the BIOS chip 100 is at a low level, and the signal Chassis_ID2 received by the BIOS chip 100 is at a high level. The BIOS chip 100 determines that the computer system is the second type, and loads corresponding programs.
The distinguishing circuit of related art, as described above, requires designers to design different motherboards to meet different types of computer systems. This is inconvenient.